Re-reeling machine for plastic film and the like

ABSTRACT

The re-reeling machine comprises a feed assembly ( 5 ) for feeding tubular winding cores and a re-reeling assembly ( 3 ) with a revolver unit ( 57 ) on which the tubular winding cores (C) are set in order to wind on them predetermined amounts of web-like material and form respective rolls (B) of wound web-like material. The revolver unit rotates about an axis of rotation (A) and has at least two supports ( 101, 102 ) for tubular cores, which are set in two angular positions with respect to said axis of rotation. The tubular-core feed assembly comprises a dispensing path ( 165, 171 ) for dispensing tubular cores to a core loader ( 181 ). The core loader is provided with a motion of approach to the revolver unit and a motion of following of the movement of the revolver unit, in order to transfer the tubular cores from the loader to the revolver unit.

TECHNICAL FIELD

[0001] The present invention relates to a re-reeling machine for theproduction of rolls of wound web-like material, and in particular (butnot exclusively), rolls of plastic material, for example extensibleplastic film.

[0002] More in particular, the present invention relates to a re-reelingmachine of the type comprising a feed assembly for feeding tubularwinding cores and a re-reeling assembly with a revolver unit on whichthe tubular winding cores are set for winding thereon pre-determinedamounts of web-like material and for forming respective rolls of woundweb-like material, said revolver unit rotating about an axis of rotationand being provided with at least two supports for said tubular cores,which are set in two respective angular positions with respect to saidaxis of rotation.

STATE OF THE ART

[0003] In the production of reels or rolls of plastic film, the filmcoming from the extruder is wound in large rolls, also referred to as“jumbo rolls” or parent reels, from which it is then unreeled to bere-reeled on rolls or reels of a smaller diameter. For this purpose,re-reeling machines are used which rewind the plastic film, delivered byan unreeler, on tubular winding cores, typically made of cardboard, toform rolls of the desired final diameter and containing the requiredamount of film.

[0004] Frequently in re-reeling machines of the above type, feed of thefilm is interrupted when a roll is completed, in order to enable cuttingof the film, unloading of the roll, insertion of a new winding core, andanchoring of the leading edge of the film to the new core, which is thenset in rotation. The cores are normally driven in rotation by aso-called central control or spindle control, namely, by applying thedriving torque to the tubular winding core.

[0005] Currently known re-reeling machines do not yield optimal resultsin terms of productivity and flexibility, understood as meaning thecapacity of the machine for adapting to cores having diameters ofvariable length.

OBJECT AND SUMMARY OF THE INVENTION

[0006] An object of the present invention is to provide a re-reelingmachine that enables one or more of the drawbacks of machines accordingto the prior art to be overcome.

[0007] More in particular, a purpose of the present invention is toprovide a re-reeling machine that enables the changeover operations,i.e., the operations for replacing the completed roll with a new windingcore in order to start winding of a new roll, in a fast and efficientway and without reducing the rate of feed of the web-like material.

[0008] Basically, according to the invention, a re-reeling machine isprovided for re-reeling web-like material, in particular plastic film,of the type referred to above, characterized in that the feed assemblyfor feeding the tubular cores comprises a path for dispensing tubularcores to a core loader, the said core loader being provided with amovement of approach to the revolver unit and a movement of following ofthe motion of the revolver unit, for transferring the tubular cores fromthe loader to the revolver unit.

[0009] This enables one or more new winding cores to be inserted intothe revolver unit while winding of the roll or rolls that are beingwound is completed. By following with the loader the movement of therevolver unit, it is for example possible to carry out the step ofangular acceleration of the core until the latter is brought up to aperipheral speed equal to that of the web-like material (the so-called“launching of the core”) by means of a device carried by the loaderitself, before the completed roll is discharged, thus also preventingthe machine from being stopped in order to carry out the changeoverstep. With this system it is theoretically possible to maintain apractically constant feed rate of the web-like material, with aconsequent increase in output. Of course, it is not ruled out that thestep for changing the roll with a new core may take place with a certainreduction in the rate of feed of the web-like material, even though thisis not strictly necessary.

[0010] According to an advantageous embodiment of the invention, then, acore-launching device, for example comprising a motor-driven rotatingmember, may be set on the core loader.

[0011] In a practical embodiment of the machine according to theinvention, the loader has at least one resting cradle for the cores thatare to be loaded into said revolver unit, said resting cradle beingmobile so as to be removed from the core once the latter is engaged bythe respective support on the revolver unit. In this way, thecore-launching device can cause angular acceleration of the core, whichis already engaged by the supporting means on the revolver unit, withoutthe movement of the core being hindered by friction against the restingcradle.

[0012] In a possible embodiment, the loader may be provided with a dualtranslation movement, namely both in the horizontal direction and in thevertical direction, to approach the revolver unit. The said dualmovement may be obtained in a simple way with two linear actuators, forinstance two cylinder-piston actuators. By adopting more preciseactuators, for example stepper motors, it is theoretically possible tocontrol movement of the loader in such a way that it will follow themovement of the revolver unit during the operations of transfer of thecore from the loader to the revolver unit and during the core-launchingstep. However, this solution presents the drawback of a considerablecost and a certain difficulty in programming the movements.

[0013] According to a preferred embodiment of the invention, instead,the loader and the revolver unit comprise mechanical members for mutualengagement, so as to co-ordinate the movement of the revolver unit withthe movement of the loader during the step of transfer of the core fromthe loader to the revolver unit and of launching of the cores. In thisway, the loader is temporarily mechanically constrained to the revolverunit, which controls movements thereof. This may be achieved, forinstance, with a bidirectional constraint, such as a hook or the like.However, in a preferred embodiment, the constraint is a supportingconstraint, and the loader is kept in contact with the revolver unit bymeans of the thrust exerted by the same actuator which controls movementof approach of the loader to the revolver unit. For the mutualengagement between the loader and the revolver unit, in a practicalembodiment there may be provided a bracket and a first idler wheel onthe loader, and a second idler wheel on said revolver unit, in theposition of mutual engagement the second wheel resting on said bracketand on said first wheel so as to exert a thrust on the loader, saidloader being in turn pushed against the revolver unit.

[0014] Advantageously, the loader may be associated to core-centringmeans. For example, a centring system may be provided comprising atleast one pair of side walls between which the said cores are made topass, the distance between said side walls being approximately equal toor slightly greater than the maximum axial length of the cores. In orderto be able to handle tubular cores even of a smaller length, thecentring system may advantageously comprise also a pair of actuators forcentring the winding cores. The pair of actuators may also be used as analternative to the side walls.

[0015] In a possible embodiment of the core-loading system, along thepath of delivery to the loader there may be provided a core-droppingpath and an oscillating dispenser which enables passage of individualcores from said core-dropping path to the loader. The said dispenser maybe interchangeable, or else may be provided with seats of differentsizes; in this way it is possible to handle cores of different radialdimensions simply by modifying the angular position of the dispenser.

[0016] In a possible embodiment, the loader may comprise a horizontalcross member which can slide along vertical guides and is associated toa first actuator or system of actuators that controls movement oftranslation along said vertical guides. Supported on said cross memberis a carriage, horizontally mobile in a direction orthogonal to saidcross member, to which a second actuator that controls horizontalmovement of the carriage with respect to the cross member is associated.Supported on the carriage is the resting cradle for the cores. Thesecond actuator may be used to push the loader against the constraintfor resting on the revolver unit during the core transfer and launchingstep.

[0017] In practice, the core-resting cradle may be carried by a bracket(either a single one or a double one) hinged to the carriage, anactuator being provided for controlling the oscillation of said bracketwith respect to the carriage.

[0018] According to a different aspect of the invention, the revolverunit may comprise, for each core support, a winding roller, which turnsat a peripheral speed that basically corresponds to the rate of feed ofthe web-like material, the tubular core or else the roll being formed onsaid core being supported idle by the corresponding support and beingpressed by the latter against the cylindrical surface of said windingroller in order to be kept rotating. In this way, winding of the rollsis of a peripheral type, instead of being of a central type as intraditional re-reeling machines provided with revolver units, and inparticular in re-reeling machines for winding plastic film.

[0019] In a practical embodiment, the core supports, provided on therevolver unit, comprise a pair of oscillating arms which carryrespective heads for frontal engagement of the cores, the oscillatingarms being displaced from a position where the core is picked up fromthe loader to a position where the core is brought up to the respectivewinding roller in order to obtain transmission of motion by friction.

[0020] Advantageously, the revolver unit may be provided with at leastone pair of guide rollers over which the web-like material is run, saidguide rollers and winding rollers being set in alternated positionsabout the axis of rotation of the revolver unit. Advantageously, alsothe guide rollers may be motor-driven, and preferably a commonmotor-power drive will be used for controlling rotation of all therollers carried by the revolver unit.

[0021] The aforesaid characteristics of the revolver unit may be adoptedalso in a re-reeling machine having a different type of core loader.

[0022] According to yet another aspect of the present invention, on therevolver unit there may be supported, for each support of the windingcores, an assembly for cutting the web-like material and applying theleading edge of the web-like material on the winding core. The abovefeature can be implemented also with a revolver unit that does notpresent the characteristics referred to above, and irrespective of thetype of core loader used.

[0023] In a practical and advantageous embodiment, each of saidassemblies for cutting the web-like material and applying the leadingedge of the web-like material on the winding core comprises a pair ofguide members over which the web-like material is run, that are parallelto one another and are set at a distance apart, and between which acutting member is set. To the cutting member it is possible to associatea blower member for pushing the free edge of the web-like material,generated by the cutting member, to wrap around the winding core.

[0024] In practice, the pair of guide members and the cutting member setbetween them may be mobile from a position set back within the path ofthe web-like material around the revolver unit, to an extractedposition, in which the guide members deviate the web-like materialaround a new core on which winding is to be started. For this purposethe guide members and cutting member can be supported on respectiveoscillating sides, which are hinged so that they can turn about the axisof the respective winding roller. The guide members may be cylinders orrollers, or else they may be made up of bars on which idle sleeves canbe supported for take-up of the web-like material.

[0025] The re-reeling machine can be configured for handling theweb-like material coming from a single jumbo roll, and hence for forminga single roll at a time. However, in order to obtain a higher output itis possible to provide a double-acting machine, i.e., one that is ableto receive two webs of material that wind in parallel on two coresaxially aligned with one another. Likewise, the core-feed system will bedouble in order to feed two cores simultaneously to the re-reelingassembly.

[0026] The re-reeling machine may be advantageously equipped with anassembly for discharging the rolls from the revolver unit. Thedischarging assembly may comprise, for instance, a mobile slide providedwith a cradle for resting the finished rolls, the mobile slide beingdisplaceable in such a way as to be brought close to the revolver unitand removed from the latter towards a roll-discharging area. The slidemay moreover be provided with a braking roller to brake the roll whenthe latter is still supported by the revolver unit, in such a way thatit can be released on the cradle of the slide after it has stoppedturning about its own axis.

[0027] Further advantageous characteristics and embodiments of there-reeling machine according to the invention are specified in theattached claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] A better understanding of the present invention will be providedby the following description and by the attached drawings, whichillustrate a practical non-limiting embodiment of the invention. More inparticular, in the drawing:

[0029]FIG. 1 is an overall and schematic side view of the re-reelingmachine equipped with the corresponding unreeler and complete with there-reeling assembly and feed assembly for feeding the winding cores;

[0030]FIG. 2 is a perspective view, from the side of the support of thejumbo rolls, of the unreeler of FIG. 1;

[0031]FIG. 3 is a perspective view, from the side of output of theweb-like material, of the unreeler of FIG. 1;

[0032]FIG. 4 shows a longitudinal cross section of the re-reelingassembly and feed assembly for feeding the tubular cores;

[0033]FIG. 4A is an enlarged view of the re-reeling assembly 3 in thesame cross section as in FIG. 4;

[0034]FIG. 4B is a cross-sectional view according to the line IV-IV ofFIGS. 4 and 4A;

[0035]FIG. 5 is a perspective view of the system for transmitting motionto the re-reeling assembly;

[0036]FIG. 6 is a side view of a detail of the re-reeling assembly;

[0037]FIG. 7 is a sectional view, according to a vertical plane, of oneof the winding rollers carried by the revolver unit of the re-reelingassembly, of the corresponding support for the winding cores, and of thedevices for cutting the web-like material and transferring it onto thenew core;

[0038]FIGS. 8 and 9 are sectional views similar to that of FIG. 7 in twodifferent positions during the step for changing the core and cuttingthe web-like material;

[0039]FIG. 10 is a side view of the core-dispensing path and of the coreloader in a position where the latter is waiting to receive a pair ofnew tubular winding cores;

[0040]FIG. 11 is a cross-sectional view according to the line XI-XI ofFIG. 10;

[0041]FIG. 12 is a sectional view, according to a vertical plane, of thecore-dispensing path and of the core loader in the position of FIG. 10;

[0042]FIG. 13 is a perspective view of the loader for loading thetubular winding cores, isolated from the remaining elements of thecore-feed assembly;

[0043]FIGS. 14 and 15 are two cross-sectional views of the loader ofFIG. 13 according to two planes orthogonal to the axis of the cores;

[0044]FIG. 16 is a perspective view of the discharge assembly fordischarging finished rolls;

[0045]FIG. 17 is a sectional view of the roll-discharging assembly,according to a plane orthogonal to the axis of the rolls; and

[0046]FIG. 18 is a schematic side view of the core loader in threedifferent positions with respect to the revolver unit during the step ofintroduction of the new winding cores.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION

[0047] The invention is described in what follows in an embodiment whichenvisages a double machine, i.e., a machine that is able to handle twowebs of material each of which is unwound from a respective jumbo roll,to form two rolls of wound material in parallel.

[0048]FIG. 1 illustrates the entire line for unreeling and re-reelingthe web-like material. The reference number 1 designates the unreeler, 3designates the re-reeling machine, and 5 an assembly for feeding thetubular winding cores. Two axially aligned parent reels or jumbo rollsare set in the unreeler for unreeling two webs of material towards there-reeling assembly 3, where pairs of rolls of web-like material of adiameter smaller than that of the jumbo rolls are formed in sequence, bybeing wound on cores supplied by the feed assembly 5.

[0049] As may be noted in FIG. 1, the plant is modular and can beequipped with further assemblies, set between the unreeler and there-reeling assembly, or even between the two components of there-reeling assembly. In this way, dinking assemblies or other assembliesmay be provided along the path of the web-like material.

[0050] The Unreeler

[0051] The configuration of the unreeler 1 is illustrated in detail inFIGS. 2 and 3, where this component of the line is shown isolated in twodifferent perspective views. The unreeler 1 has two sides 7 joinedtogether by cross members 9. The two sides 7 support two deliveryrollers 11, 13, over which two unwinding belts are run. The bottomdelivery roller 11 is motor-driven in the way described in what follows,and draws along the belts 15, and consequently the top roller 13.

[0052] Two parent reels are pressed against the corresponding belts 15.One of said prent reels rolls is partially illustrated in FIG. 1 anddesignated by BM. The web-like material N is delivered, by the parentreels, to be wound into rolls of a smaller diameter by means of there-reeling assembly 3. The parent reels BM are each held by a pair ofidle centres, designated by 17, 19, and carried by respective arms 21,23 connected together by torsion bars 25. A cylinder-piston actuator 27(FIG. 3) acts on the arm ensemble to move the arms 21, 23 alternativelyinto a loading position or into an unreeling position. In the latterposition, the arms press the parent reels BM, which are carried by therespective centres 17, 19, against the belts 15. Movement of the latterbrings about unreeling of the web-like material. Above the deliveryroller 13 is a feed roller 29 around which the web-like material unwoundfrom the parent reels BM is run.

[0053] On the opposite side of the unreeler with respect to the arms 21,23 for supporting the parent reels BM, there are two pairs of idle guiderollers, one of which is designated by 31 and the other by 33, aroundwhich the web-like material coming from the parent reels BM is run. Thepath of the web-like material is illustrated in FIG. 1 and designated byN. One of the rollers of each pair has an axis which can be inclined bymeans of an actuator (not illustrated) and a sensor for detecting theedge position of the web-like material running over the guide roller. Bymeans of the sensor it is possible to check that the web-like materialalways remains properly guided. Any swerving of the web-like material iscorrected by modifying the inclination of the axis of the inclinableroller.

[0054] On one of the two sides of the unreeler is the motor-power driveand transmission of movement to the various members, illustrated inparticular in FIG. 2. The reference number 35 (see also FIG. 3)designates the main motor, which transmits motion to the members of theunreeler by means of a belt 37 run over a series of pulleys, which areshown in FIG. 2. Of the latter, the ones designated by 39 and 41 are thepulleys set respectively on the shaft of the feed roller 29 and on theshaft of the bottom delivery roller 11.

[0055] Set above the feed roller 29 are two arms 43 to which printingunits (not shown) are applied to print wordings or other markings on theweb-like material that is being unreeled.

[0056] The Re-Reeling Assembly

[0057] The re-reeling assembly 3 is illustrated in detail in FIGS. 4, 4Aand 4B. Set at intake to the re-reeling assembly is a hump roller 51 forstretching the web-like material N in the transverse direction andeliminating any longitudinal creases. Downstream of the hump roller is aguide roller 55 which deflects the path of the web-like material Ntowards a revolver unit 57 supported so that it can turn about ahorizontal axis A, which develops in the direction of the width of theweb-like material N, i.e., in a direction orthogonal to the plane ofFIGS. 4 and 4A.

[0058] Supported on the revolver unit 57 are two winding rollers 59, 61and two guide rollers 63, 65. The two winding rollers 59, 61 are setwith their own axes in a plane in which the axis A of rotation of therevolver unit lies. Likewise, the axes of the guide rollers 63, 65 areset in a plane in which the axis A lies. The latter rollers are at adistance from the axis A greater than that of the winding rollers 59,61.

[0059] All the winding rollers 59, 61 and guide rollers 63, 65 aremotor-driven by a single motor which also drives the guide roller 55.The corresponding transmissions are set on the outside of the sides 67and 69, as may be seen in FIGS. 4 and 4A. FIG. 5 is a perspective viewof the motor and drives isolated from the other members of there-reeling assembly 3. The reference number 71 designates the motorwhich transmits, by means of a belt 73 and a pulley 75, motion to a mainshaft 77. From the latter, by means of a belt 79, the motion istransmitted to the guide roller 55, at the corresponding end of which apulley 81 is fitted. From the same shaft 77, by means of a pulley 83,the motion is transmitted to a pulley 85 which is supported idle on theshaft of the revolver unit. The pulley 85 is double, and a further belt87 is run over it, which transmits motion to four pulleys 89, 90, 91 and92. The pulleys 89 and 90 are fitted on the shafts of the windingrollers 59, 61, whilst the pulleys 91, 92 are fitted on the shafts ofthe guide rollers 63, 65. In this way, all the rollers carried by therevolver unit are motor-driven and rotate at the same speed, which iscontrolled by the motor 71. The peripheral speed of the rollers isapproximately equal to the rate of feed of the web-like material N.Fitted on the shaft with axis A of the revolver unit is a chain wheel 93over which a chain 95 is run, the said chain being driven by a motorreducer 97. The motor reducer is responsible for the rotational movementof the revolver unit 57 about its own axis, for the purposes which willbe clarified in what follows. This rotation takes place at a much lowerspeed than the rate of feed of the web-like material.

[0060] On the revolver unit 57 there are provided, for each of thewinding rollers 59, 61, respective supports for winding rolls. As may beseen in particular in the cross section of FIG. 4B, associated to eachwinding roller 59, 61 are two pairs of heads 101, 102. Each pair ofheads 101, 102 has the function of engaging a respective tubular windingcore; in this way, alongside each winding roller 59, 61 there are twoaxially aligned winding cores. Each head is carried by a respectiveoscillating arm, designated by 103 and pivoted about an axis 105parallel to the axis A of the revolver unit 57. The heads can move in adirection parallel to the axis A of the revolver unit, so that they canengage a respective winding core and disengage therefrom.

[0061] Each pair of heads 101, 102 and the corresponding oscillatingarms 103 form a support for a winding core and for the roll that formsthereon during feed of the web-like material. An actuator (notillustrated) can take the pairs of oscillating arms with thecorresponding heads from the position shown in FIG. 4 to a positionwhereby the tubular winding core engaged by the heads comes to pressagainst the surface of the respective winding roller 59, 61. Thismovement is shown in particular in FIGS. 7, 8 and 9. In FIG. 7, the head101 is shown in the position where it is at some distance away from therespective winding roller 57, whilst in FIGS. 8 and 9 it is brought upto the winding roller. In this configuration, the core C supported bythe heads, or the outer surface of the roll being formed thereon, ispressed against the winding roller 59 for receiving, by friction, thedrawing torque that keeps the core and the roll being formed thereonrotating, thus enabling re-reeling to be carried out.

[0062] The movement of approach the winding core to the second windingroller 61 takes place in a similar way.

[0063] Pivoted around the shafts of each of the two winding rollers 59,61 are two sides 111 (one of which is shown in FIGS. 4, 4A, 7, 8, and 9,the other being identical and being set at the opposite end of therespective roller). Each of the two sides 111 supports two bars 113, 115on each of which idle sleeves 117, 119 are set, over which, in theroll-changeover step, web-like material is run, as will be clarifiedhereinafter. The two sides 111, and consequently the members supportedthereby, oscillate about the axis of the respective winding roller 59 or61 by means of an actuator (not illustrated), which takes the sides 111and the members supported thereby from the position of FIG. 7 to theposition of FIG. 8 in order to carry out changeover of the windingcores, as will be clarified in what follows.

[0064] Set between each pair of sides 111 is also a cutting member,designated as a whole by 121 (see in particular FIGS. 7-9), whichcomprises a pair of oscillating arms, only one of which may be seen inthe drawing and is designated by 123. The oscillating arms are pivotedabout an axis X (FIGS. 8 and 9) fixed with respect to the sides 111 andcarry a bar 125, which extends between the sides 111 and carries acutting blade 127 heated by an electrical resistor 129 in contacttherewith. The bar 125 also carries, alongside the cutting blade 127, aseries of compressed-air nozzles, designated by 133.

[0065] The oscillating arms are controlled by an actuator 131, which isalso carried by one of the sides 111. The actuator 131 causes thecutting blade 127 to assume two alternative positions with respect tothe bars 115. One of these alternative positions is shown in FIGS. 7 and8 and the other in FIG. 9. The movement controlled by the actuator 131has the purpose of cutting the web-like material at the moment of changeof the winding core, as will be clarified later.

[0066] The ensemble made up of the elements 111-133 forms a cuttingassembly for cutting the web-like material and applying the leading edgeof the web-like material on the new winding core.

[0067] Operation of the members described above with particularreference to FIGS. 4, 4A, 4B, 7, 8, and 9 will be illustrated in furtherdetail in what follows.

[0068] Provided on the revolver unit 57, in an intermediate positionalong its axis A and approximately at the height of each of the twoassemblies of winding-core supporting heads, are two respectiveprojecting arms 104, one of which may be seen in particular in FIGS. 8and 9, whilst the other is symmetrical with respect to the axis A of therevolver unit. Each projecting arm 104, which is rigidly constrained tothe revolver unit, carries an idler wheel 106 which has the function ofcreating a constraint between the revolver unit and the core loaderduring the step of replacement of the winding rolls, in the way thatwill be clarified hereinafter. The two arms 104 and the respectivewheels 106 protrude beyond the overall dimensions of the revolver unit57, as may be seen in FIG. 6.

[0069] The re-reeling assembly 3 moreover comprises an assembly fordischarging the finished rolls, which is designated as a whole by 135and shown in detail in FIGS. 16 and 17. The discharging assembly 135 hasa mobile slide 137 fixed to two tubular guide bars 139 which are guidedby means of shaped rollers 141 (cf. FIG. 16) that are idly supported onshafts fixed to the load-bearing structure of the re-reeling assembly.Movement of the slide is controlled by a cylinder-piston actuator 143.The slide can assume a retracted position (FIGS. 4 and 4A) and aposition where it is brought up to the revolver unit 57 for receiving afinished roll and removing it from the revolver unit, according tomodalities which will be described in greater detail in what follows.

[0070] Carried on the slide 137 is a braking roller 145 with anelectromechanical brake 147. When the slide 137 is in the position closeto the revolver unit, the braking roller 145 is in contact with thecompleted roll, which is still supported by the heads 101, 102 thatengage the corresponding core. The heads have been brought into aposition at a distance from the respective winding roller 59 or 61, andhence the contact of the roll with the braking roller 145 will causearrest of the inertia rotation of the roll itself.

[0071] The slide 137 also carries a cradle for resting the finishedroll, or the two axially aligned finished rolls, when the latter arereleased from the heads 101, 102. The cradle is designated by 151 forboth of the rolls and is formed by respective pairs of lengths of openV-shaped section, designated by 151A. Set between the two lengths ofV-shaped section is a side wall 153, which can move vertically under thecontrol of a cylinder-piston actuator 155. In the raised positionillustrated in FIGS. 16 and 17, the mobile side wall prevents accidentaldropping of the roll that is positioned on the cradle, whereas, when itcomes down it enables discharge of the roll from the cradle onto adischarge conveyor belt set underneath. Between each pair of lengths ofV-shaped section 151A and on the opposite side with respect to themobile side wall 153, there is set a pusher 159 operated by acylinder-piston actuator 161. The pusher 159 pushes the finished rollout of the respective cradle 151 and causes it to drop onto the conveyorbelt 157.

[0072] The Core-Feed Assembly

[0073] The tubular cores are fed to the re-reeling assembly 3 by thefeed assembly 5, which is shown in particular in FIGS. 4 and 10 to 15.This assembly comprises a double hopper 161 from which the tubular coresare picked up by a double conveyor belt 163 which takes them to a doublechute 165. The arrangement is double to make it possible to pick up andfeed pairs of axially aligned tubular cores, which receive the web-likematerial delivered by the two parent reels BM unwound in parallel in theunreeling assembly 1.

[0074] Along the conveyor belt 163 there develop side walls 167, andalong the chute 165 there develop side walls 169 for centring thetubular cores. Centring is obtained when the tubular cores have a lengthapproximately equal to or slightly smaller than the distance between theside walls, i.e., the width of the conveyor belt 163 and chute 165. Whenthe cores have a smaller length, they must be re-centred with a specialcentring system described hereinafter.

[0075] Connected underneath the chute 165 is a dropping channel or path171 for dropping the cores, within which an oscillating dispenser 173 isset, which is shown in detail in the enlarged cross section of FIG. 12.The oscillating dispenser 173 oscillates about its own axis 173X underthe control of a cylinder-piston actuator 175 (FIG. 10). As may be seenin FIG. 12, the oscillating dispenser 173 has two seats 173A and 173B ofdifferent sizes for receiving tubular cores C having differentdiameters. FIG. 12 illustrates the tubular cores C respectively with themaximum diameter—designated by C1— and the minimum diameter—designatedby C2—that can be handled by the machine. In the configurationrepresented in FIG. 12, the oscillating dispenser is positionedangularly in such a way as to handle the cores C1 of larger diameter.The latter are picked up from the chute 165 and transferred into thedropping channel or path 171 by means of an oscillation, as indicated bythe arrow f173, of the oscillating dispenser 173. When the device is tohandle cores C2 of a smaller diameter, its angular position is modifiedby 180° to change round the positions of the two seats 173A and 173B.The core C2 shown in FIG. 12 is therefore represented only in order toillustrate how the machine is able to handle tubular cores having evenwidely variable diameters.

[0076] The tubular core unloaded by the oscillating dispenser 173 comesdown along the dropping path 171 until it reaches the position C1′ (forthe core C1) or C2′ (for the core C2) on a core loader 181 illustratedin detail and isolated from the other elements of the assembly 5 inFIGS. 13 to 15. When the core reaches the bottom position along thedropping path, it can be centred (when its size is considerably smallerthan the distance between the sides 169 of the chute 165) by means ofcentring devices controlled by pairs of actuators 180 (FIG. 11)positioned at the bottom of the dropping channel 171.

[0077] The loader 181 comprises a horizontal cross member 183 which isfixed to guide bushings 185 that slide along vertical guide bars 187.The movement in the vertical direction is supplied to the cross member183 by a cylinder-piston actuation system 189 which controls themovement of vertical translation of the loader 181, as indicated by thedouble-headed arrow f181. In the example of embodiment illustrated, theactuation system 189 consists of two cylinder-piston actuators 189A,189B set in series, the operation of which is explained in greaterdetail in what follows.

[0078] Applied underneath the horizontal cross member 183 are two guidebushings 191, in which there slide bars 193 of a carriage 195, whichcarries the cradles for resting the cores that are to be inserted intothe re-reeling assembly. A cylinder-piston actuator 197, the cylinder ofwhich is constrained to a bracket 199 fixed to the cross member 183, andthe stem of which is constrained to the carriage 195, controls movementof the carriage 195 in the direction indicated by the double-headedarrow f195, the said direction being orthogonal to the cross member 183and to the guide bars 187.

[0079] Hinged to the carriage 195 are two double L-shaped brackets,designated by 201, which oscillate with respect to the carriage 195about an axis 201A (see in particular FIGS. 12 and 15) that is parallelto the cross member 181. The oscillation of each double bracket 201about the axis 201A is controlled by a respective cylinder-pistonactuator 203, the stem of which is constrained to a cross member 205that joins the two parts of the double L-shaped bracket 201 together.The double bracket 201 oscillates in the direction indicated by thearrow f201 in FIGS. 14 and 15. A pair of lengths of section 202 isconstrained to the double bracket. The lengths of section 202constrained to each double bracket 201 form respective cradles for thetubular winding cores C.

[0080] Fixed to each double bracket 201 is an upright 207 which supportsa further cylinder-piston actuator 209. Each upright 207 and thecorresponding actuator 209 thus oscillate rigidly together with therespective bracket 201 when the actuator 203 is operated. The stem ofeach actuator 209 is constrained to a shaft 211 with interposition of abearing that enables the shaft 211 to turn about its own axis and to bedisplaced at right angles to the axis itself as a result of the actionof the actuator 209.

[0081] Fitted on the shaft 211 are two friction wheels 215, which havethe function, as will be described later, of imparting an angularacceleration on the winding core before this comes into contact with theweb-like material that is to be wound thereon. The rotation of eachshaft 211, and hence of the friction wheels 215, is controlled by amotor 217 axially aligned with the shaft itself. Each shaft 211 issupported by a pair of oscillating arms 213, which are pivoted to thedouble bracket 201 about the axis of the cross member 205. The actuator209 can thus cause an oscillation of the shaft 211 about the axis of thecross member 205. The two positions of the shaft 211 are represented onein FIGS. 13-15 and the other in FIG. 12. This oscillation makes itpossible to bring the friction wheels 215 into a position in which theydo not interfere with the dropping of the winding cores C along the path171.

[0082] Mounted on the carriage 195, in an intermediate position betweenthe two pairs of brackets 201, is a bracket 221, through which thecross-sectional plane of FIG. 15 passes. An idler wheel 223 is supportedidle on the bracket 221. The bracket 221 and the idler wheel 223 aredesigned to co-operate with either one or the other of the idler wheels106 (FIGS. 8 and 9) of the revolver unit for creating a temporaryconstraint between the core loader and the revolver unit itself.

[0083] Operation of the Machine

[0084] The machine so far described operates as explained in whatfollows. Set on the unreeler 1 are two parent reels or jumbo rolls BM,which are pressed against the unwinding belts 15. The movement of thelatter, controlled by the motor 35, causes gradual unreeling of theweb-like material N which is fed as far as the revolver unit 57 of there-reeling assembly 3 to be wound into rolls B of a smaller diameteraround the winding cores C.

[0085]FIG. 4A shows the re-reeling assembly 3 in a step of completion ofa pair of axially aligned rolls B. The two rolls being completed, onwhich the web-like materials coming from the two parent reels BM arebeing wound, are supported by the two pairs of heads 101, 102, which arein the position closest to the unreeler 1 and closest to the dischargeconveyor belt 157, i.e., at the bottom left in FIG. 4A. In thisconfiguration, the web-like material N coming from each of the twoparent reels BM is run over the guide rollers 63, 65 and the windingroller 59. The rolls are pressed by the corresponding supports againstthe winding roller 61, which furnishes the winding motion.

[0086] The angular position of the revolver unit 57 shown in FIG. 4B isactually reached upon completion of the rolls B, when the new cores havealready been inserted into the re-reeling assembly for carrying out thechangeover, i.e., cutting of the web-like material and transfer of theleading edge onto the new core.

[0087] During the step of winding of a core, two winding cores C havebeen prepared on the core loader 181 (on the cradles 202) and will betransferred to the revolver unit 57 once winding of the rolls B has beencompleted.

[0088] When the desired amount of web-like material is wound on therolls B, the changeover step starts, i.e., the step of replacement ofthe completed rolls with the new winding cores. In the changeover step,for each core and for each finished roll, the following operations areto be carried out:

[0089] insertion of the new cores into the revolver unit 57;

[0090] angular acceleration of the new cores;

[0091] cutting of the web-like material;

[0092] winding of the free leading edge of the cut web-like material onthe corresponding core; and

[0093] discharge of the completed roll.

[0094] For this purpose, the loader 181 with the new cores is brought upto the revolver unit 57 until it reaches, with the core-supportingcradles, the position indicated by P1 in FIG. 18, by means of a combinedhorizontal and vertical movement (respectively controlled by theactuators 197 and 189A) of the carriage 195. The revolver unit 57 is inan angular position whereby the heads 101, 102 associated to the windingroller 59 (temporarily inoperative) are aligned with the cores carriedby the carriage of the loader to the position P1. At this point, theheads can engage the cores themselves, which are thus withheld on therevolver unit 57 and no longer require the resting position provided bythe cradles formed by the lengths of section 202.

[0095] In this step, the position of the carriage 195 of the core loaderwith respect to the revolver unit 57 is such that the idler wheel 106associated to the winding roller 59 comes to rest against the bracket221 and against the idler wheel 223, which are supported by the carriageitself. There is thus created a unidirectional constraint between thecarriage 195 of the loader 181 and the revolver unit 57. The constraintis guaranteed by the fact that the carriage is constantly pressedagainst the revolver unit by the (reduced) pressure, which is in anycase maintained in the cylinder of the actuator 197 and in the actuator189B.

[0096] The two cylinder-piston actuators 189A, 189B making up the system189 thus have two distinct functions: the former controls the movementof vertical translation necessary for bringing the carriage into theposition P1 of FIG. 18, whilst the latter has the function of applyingthe horizontal reaction force for maintaining contact between theengagement members, with mutual engagement between the carriage of theloader and the revolver unit.

[0097] From the above configuration, the revolver unit starts turning inthe clockwise direction (FIGS. 4, 4A, 7, 8, 9, and 18), as indicated bythe arrow f57, about its own axis A. Thanks to the constraint formed inthe way described above between the revolver unit 57 and the carriage195 of the loader 181, the carriage itself follows the movement of therevolver unit. In this step, the rollers carried by the revolver unitkeep rotating at normal running speed, feeding the web-like material,which is delivered by the unreeler to the respective roll B that isbeing formed and is about to be completed.

[0098] As rotation of the revolver unit 57 proceeds, until it reachesthe position illustrated in FIGS. 4 and 4A, the brackets 201 carried bythe carriage 195 are made to oscillate downwards by the cylinder-pistonactuator 203, so that they will lose contact with the respective core C.This movement of oscillation also brings the friction wheels 215 intocontact with the cylindrical surface of the corresponding core, which iswithheld in position by the heads 101,102 of the revolver unit 57.

[0099] Actuation of the motor 217 causes the rotation of thecorresponding core thanks to the friction between the latter and thefriction wheels 215. The operation of angular acceleration of the cores(and of the heads supporting them) is referred to as “core launching”and has the function of bringing the peripheral speed of the core up toa value approximately equal to the rate of feed of the web-likematerial, so that the subsequent contact between the latter and the corewill take place without any mutual sliding, or at least with onlyminimal sliding.

[0100] When the core-launching operation has been completed, i.e., whenthe core has reached the required peripheral speed, the carriage 195 hasreached (following the rotation of the revolver unit 57) the position P2of FIG. 18. In this position, the oscillating arms 103 are made tooscillate until the core C, withheld by the heads 101, 102, is broughtinto contact with the web-like material N that is run over the windingroller 59. The movement of approach of the core is represented in FIG. 7(arrow f101.

[0101] When each of the two coaxial tubular cores touches the web-likematerial N run over the surface of the winding roller 59, it receivesmotion via the web-like material as a result of the underlying windingroller 59, so that the carriage 195 of the loader 181 can be moved away,by means of the actuators 197 and 187, to return to the initial positionunderneath the dropping path 171 of the cores, for receiving a new pairof cores.

[0102] When the new cores are in the position in which the launchingoperation has been completed (position P1 in FIG. 18), the pair ofalmost completed rolls B is in the discharging position, ready to bedischarged after prior cutting of the web-like material.

[0103] The operation of cutting of the web-like material and of windingof the leading edge on the new core C is carried out according to thesequence illustrated in FIGS. 7 to 9. When the core C is in contact withthe web-like material N run over the winding roller 59, the sides 111carrying the bars 113, 115 oscillate in the counter-clockwise direction(FIGS. 7-9), as indicated by the arrow f111, about the axis of thewinding roller 59 to pass from the position of FIG. 7 to the position ofFIG. 8. During this movement, the web-like material N rests on theinternal surface of the web-like material N, namely on the surfacefacing the axis of the revolver unit 57, and, at the end of the movementof the sides 111, the web-like material comes to describe a path whichembraces the core C for approximately three quarters of thecircumferential development thereof, and which then develops around thesleeves 117, 119 supported idle on the bars 113 and 115.

[0104] At this point, cutting of the web-like material can be carriedout by means of extraction of the cutting blade 137, which moves fromthe set-in position of FIG. 8 to the extracted position of FIG. 9. Inparticular, when the web-like material is a plastic film, the blade 127is appropriately heated in order to facilitate the cutting operation.Alternatively, a hot wire or another suitable cuffing means could beused.

[0105] The free leading edge that is formed with the cutting operationis wound around the core C with the aid of jets of air generated by theblower nozzles 133. The trailing edge is recalled around the completedroll B, in so far as the latter is kept in contact with the windingroller 61 until the trailing edge has been completely re-wound.

[0106] When the trailing edge is completely wound on the roll B, thelatter is moved away from the winding roller 61 and discharged, by meansof opening of the heads 101, 102, onto the cradle 151 of the slide 135,which in the meantime has moved to the roll-pickup position. Before theheads 101, 102 are opened, and hence before the completed roll isdischarged onto the cradle 151, inertial rotation of the roll is brakedby means of the braking roller 145.

[0107] After the roll B has been discharged onto the cradle 151, theslide 135 is brought back into the low position (FIG. 4), and, by meansof the pusher 159, the roll is discharged onto the discharge belt 157.

[0108] At this point, the revolver unit 57 can start approaching theangular position in which the winding rollers 59 and 61 swap theirpositions to carry out the next roll-changeover cycle.

[0109] It is understood that the drawings only illustrate only apractical embodiment of the invention, which may vary in its embodimentsand arrangements without thereby departing from the scope of theunderlying idea. The possible presence of reference numbers in theattached claims has the sole purpose of facilitating reading thereof inthe light of the foregoing description and of the annexed drawings, andin no way limits the scope of protection represented by the claims.

1. A re-reeling machine for re-reeling a web-like material, inparticular plastic film, comprising a feed assembly for feeding tubularwinding cores and a re-reeling assembly with a revolver unit on whichthe tubular winding cores are set for winding thereon pre-determinedamounts of web-like material and for forming respective rolls of woundweb-like material, said revolver unit rotating about an axis of rotationand being provided with at least two supports for said tubular cores,which are set in two respective angular positions with respect to saidaxis of rotation, characterized in that said feed assembly for feedingthe tubular cores comprises a path for dispensing tubular cores to acore loader, said core loader being provided with a motion of approachto the revolver unit and a motion of following the movement of therevolver unit, in order to transfer the tubular cores form the loader tothe revolver unit.
 2. The machine according to claim 1, characterized inthat said loader comprises a core-launching device for setting thetubular cores in rotation before starting winding of the web-likematerial on the cores.
 3. The machine according to claim 2,characterized in that the core-launching device comprises a motor-drivenrotatable member.
 4. The machine according to one or more of theforegoing claims, characterized in that said loader and said revolverunit comprise members for mutual engagement in order to co-ordinate themovement of the revolver unit with the movement of the loader in thestep of transfer of the core from the loader to the revolver unit and oflaunching of the cores.
 5. The machine according to one or more of theforegoing claims, characterized in that said loader has at least onecradle for resting the cores that are to be loaded onto said revolverunit, said resting cradle being movable so as to be removed from thecore once the latter has been engaged by the respective support on therevolver unit.
 6. The machine according to one or more of the foregoingclaims, characterized in that said loader is provided with a dual motionof translation, namely both in the horizontal direction and in thevertical direction, so as to come up to the revolver unit.
 7. Themachine according to claim 4, characterized in that said members formutual engagement comprise, on the loader, a bracket and a first idlerwheel, and, on said revolver unit, a second idler wheel, in a positionof mutual engagement between said loader and said revolver unit, thesecond wheel resting on said bracket and on said first wheel so as toexert a thrust on the loader, said loader being in turn pushed againstthe revolver unit.
 8. The machine according to one or more of theforegoing claims, characterized in that said loader comprises means forcentring the cores.
 9. The machine according to one or more of theforegoing claims, characterized in that said path for dispensing thecores to the loader comprises a path for dropping the cores and anoscillating dispenser which enables passage of individual cores fromsaid dropping path to the loader.
 10. The machine according to claim 9,characterized in that said oscillating dispenser comprises two distinctseats for receiving individual cores that are to be transferred to theloader, said two seats having different dimensions and being usedalternatively according to the size of the diameters of the cores. 11.The machine according to one or more of the foregoing claims,characterized in that said loader comprises a horizontal cross member,which can slide along vertical guides, and in that supported on saidcross member is a carriage which can move horizontally in a directionorthogonal to said cross member, said at least one cradle for restingthe cores being supported on said carriage.
 12. The machine according toclaim 11, characterized in that said cradle for resting the cores iscarried by a bracket hinged to said carriage, an actuator being providedfor controlling oscillation of said bracket with respect to thecarriage.
 13. The machine according to claims 2 and 12, characterized inthat supported on said bracket is said core-launching device, themovement of oscillation of the bracket bringing the launching deviceinto contact with the cylindrical surface of the core when the latter issupported by the revolver unit.
 14. The machine according to claim 13,characterized in that said launching device is carried by a pair ofoscillating arms hinged to said bracket, an actuator being provided forcausing said arms to oscillate with respect to said bracket.
 15. Themachine according to one or more of the foregoing claims, characterizedin that said revolver unit comprises, for each core support, a windingroller, which turns at a peripheral speed substantially corresponding tothe rate of feed of the web-like material, the tubular core, or else theroll being formed on said core, being supported idle by thecorresponding support and being pressed by the latter against thecylindrical surface of said winding roller so as to be kept in rotation.16. The machine according to claim 15, characterized in that each ofsaid core supports comprises a pair of oscillating arms which carryrespective heads for frontal engagement of the cores, the oscillatingarms being displaced from a position where they take the core from theloader to a position where the core is brought up to the respectivewinding roller.
 17. The machine according to claim 15 or claim 16,characterized in that said revolver unit has at least one pair of guiderollers over which the web-like material is run, said guide rollers andsaid winding rollers being set in alternated positions about the axis ofrotation of the revolver unit.
 18. The machine according to claim 17,characterized in that said guide rollers are motor-driven.
 19. Themachine according to claim 18, characterized in that said guide rollersand said winding rollers are driven into rotation by means of a singlebelt which receives motion from the shaft of the revolver unit.
 20. Themachine according to one or more of the foregoing claims, characterizedin that supported on said revolver unit, for each support for thewinding cores, is an assembly for cutting the web-like material andapplying the initial or leading edge of the web-like material on thewinding core.
 21. The machine according to claim 20, characterized inthat each of said assemblies for cutting the web-like material andapplying the leading edge of the web-like material on the winding corecomprises a pair of members over the web-like material is run, which areparallel to one another and set at a distance apart, and between which acutting member is set.
 22. The machine according to claim 21,characterized in that associated to said cutting member is a blowermember for pushing the free edge of the web-like material, generated bysaid cutting member, to wrap round the winding core.
 23. The machineaccording to claim 21 or claim 22, characterized in that said pair ofguide members and said cutting member set between them can move from aposition set back within the path of the web-like material around therevolver unit, to an extracted position, in which the guide membersdeflect the web-like material around a new core on which winding is tostart.
 24. The machine according to claims 15 and 23, characterized inthat said pair of guide members and said cutting member are supported byrespective oscillating sides, which are hinged about the shaft of therespective winding roller.
 25. The machine according to one or more ofclaims 21 to 24, characterized in that said guide members are made up ofbars on which idle sleeves are supported over which the web-likematerial is run.
 26. The machine according to one or more of theforegoing claims, characterized in that the supports for the cores aredouble so that each supports one of the two axially aligned windingcores, and in that two parallel paths are provided for two web-likematerials that are fed simultaneously to the machine.
 27. The machineaccording to claim 26, characterized in that the loader is double so asto present simultaneously to the revolver unit two winding cores thatare substantially axially aligned.
 28. The machine according to one ormore of the foregoing claims, characterized in that it comprises adischarge assembly for discharging the cores from said revolver unit,said discharge assembly comprising a mobile slide, provided with aresting cradle for the finished rolls, the mobile slide beingapproachable to the revolver unit and removable from the latter to acore-discharging area.
 29. The machine according to claim 28,characterized in that said slide carries a braking roller for brakingthe roll.
 30. The machine according to claim 28 or claim 29,characterized in that said cradle has at least one safety bracket forretention of the roll in said cradle, the said safety bracket beingassociated to an actuator for it to be opened and closed.
 31. Themachine according to claim 30, characterized in that associated to saidslide is a pusher for expelling the roll from said cradle to a dischargeconveyor.
 32. The machine according to one or more of the foregoingclaims, characterized in that associated to said core loader is acentring system for centring the cores before they are introduced intothe revolver unit.
 33. The machine according to claim 32, characterizedin that said centring system comprises at least one pair of side wallsbetween which said cores are made to pass, the distance between saidside walls being approximately equal to or slightly greater than themaximum axial length of the cores.
 34. The machine according to claim 31or claim 32, characterized in that said centring system comprises atleast one pair of actuators for centring of the winding cores.
 35. Themachine according to one or more of the foregoing claims, characterizedin that it has a modular structure.
 36. The machine according to one ormore of the foregoing claims, characterized in that it comprises anunreeler equipped with one or more printing heads.
 37. The machineaccording to claim 36, characterized in that said unreeler has a dualsupport for two parent reels of web-like material that are to be unwoundsimultaneously.